WOW welcomed at least 100 people on Saturday, according to co-owner Rich Wilson.

“We had about 40 people in here at one time,” said Wilson, 53, who opened the town’s first frozen yogurt shop ever with his friend, 52-year-old Dan Whalen.

Wilson and Whalen, both from South Hadley, renovated the building that sits between CVS and Nap’s auto shop. It most recently housed a video game store.

Wilson said he’s been visiting Greenfield weekly for many years.

“When we looked at where we’d want to open, we thought about location, whether there would be a lot of children and young people in the area, how many schools there were, what the traffic counts were like, and how many businesses would be doing the same thing we were,” said Wilson.

He said 20,000 cars travel Federal Street each day, there are four schools within walking distance of WOW, it is close to the downtown and the hospital, and the location gets a good car and foot traffic count.

“There’s also ample parking,” said Wilson. “I grew up in the area and have come to Greenfield my entire life. This seemed like the perfect place, and we were right; everyone has been so welcoming.”

Wilson said WOW, which occupies the northern-most 1,200 square feet of the building, is not a chain.

He said the self-serve frozen yogurt shop will rotate 49 flavors, offering eight each day. He said their frozen yogurt is the best kind, because it contains active yeast cultures.

A combination of chocolate and sweet coconut is liking having a Hershey’s Mounds candy bar, said Wilson, who also said there will be something for everyone, including regular, low-fat, nonfat, low-calorie, no-calorie, dairy-free and no-sugar frozen yogurt.

“There will always be a surprise,” he said.

Wilson said they will be adding Greek Euro-Tart frozen yogurt for those who have asked for a tangier treat.

He said customers walk in, grab the size cup they want, fill it with one or more flavors of frozen yogurt, choose from 50 toppings, 10 sauces and whipped cream, and place their creations on a scale. There are sample cups available for those who cannot make up their minds.

The price is 55 cents per ounce.

“People are having a ball,” he said. “They were coming in when the temperature was below zero and eating frozen yogurt.”

Wilson said the two are planning a grand opening for February.

There is enough room at two counters for people to sit and enjoy frozen yogurt, but they may also take it with them, said Wilson.

A mounted flat-screen television plays videos and music and televises weather and sports throughout the day.

Wilson said red velvet cake and New York cheesecake will be two of the flavors to arrive soon.

WOW also sells health drinks, including water and Glaceau vitaminwater.

Wilson, who has worked in banking and transcription, and Whalen, who is a carpenter and general contractor, hope to lease the other 1,200-square-foot space to another retailer.

The two men have been friends for 25 years and said they always wanted to go into business together.

Wilson and Whalen said they did their research, finding that frozen yogurt has been popular on the West Coast for about a decade, developed a business model, and decided they wanted to open something that would have people smiling.

“Frozen yogurt was it,” said Wilson. “We saw a growing trend headed this way and decided to get in on it.”

Wilson said neither had worked in the food industry before now.

WOW has free parking on the north side of the building and in front on Federal Street. The shop is open Monday and Tuesday from noon to 6 p.m. and Wednesday through Sunday from noon to 8 p.m. Credit cards are accepted.